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El primer dinosaurio terópodo de Rincón de los Sauces es un abelisaurio
0 comentarios Publicado por Leonardo Filippi en 5:38
Avanza la preparación del primer ejemplar de
dinosaurio terópodo recuperado recientemente en la última campaña
paleontológica del MAU en La Invernada. Entre los materiales que ya han sido
preparados se cuentan: varias costillas cervicales y dorsales, además
de vértebras caudales y cervicales. En estos días esta finalizando la
preparación de los restos craneanos, que si bien no se encuentra completo,
aportarán relevante información. Si bien, aún queda mucho material sin preparar
en el laboratorio del museo, y seguramente por extraer del campo, los elementos
que ya se disponen ponen en clara evidencia que el ejemplar corresponde a un
abelisaurio el cual habría alcanzado unos 5 m de longitud. Los abelisaurios son
un grupo de dinosaurios terópodos principalmente gondwánicos, es decir,
habitaron el supercontinente de Gondwana, conformado por Sudamérica,
África, India, Australia y la Antártida. Recientemente se ha dado a conocer
un nuevo abelisaurio, Arcovenator escotae,
el primero proveniente de Europa, lo que sugiere algún tipo de conexión
biogeográfica entre Europa y Africa a finales del Cretácico. El abelisaurio de
La Invernada, proviene de niveles de la Formación Bajo de la Carpa, los mismos
niveles de donde fueron recuperados en la misma campaña a unos 300 m de
disntancia, al menos dos ejemplares de dinosaurio sauropodo titanosaurio. Estos
materiales aportan interesante información respecto de una asociación
faunística donde queda demostrado quien cumplía el papel de depredador y quién
el de presa. En la medida que los fósiles sean preparados, daremos a conocer
más información respecto de este nuevo carnívoro patagónico.
Foto ilustrativa: Sergey Krasovskly
Evolution of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia
0 comentarios Publicado por Leonardo Filippi en 8:48
Fernando
E. Novas, Federico L. Agnolín, Martín D. Ezcurra, Juan Porfiri and
Juan
I. Canale
Novas, F.E., Agnolín,
F.L., Ezcurra, M.D., Porfiri, J.D., Canale, J.I. 2013. Evolution
of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia.
Cretaceous
Research 45:174–215.
March of the Titans: The Locomotor Capabilities of Sauropod Dinosaurs.
0 comentarios Publicado por Leonardo Filippi en 3:56
William
Irvin Sellers1, Lee Margetts, Rodolfo Aníbal Coria, Phillip Lars Manning
Sauropod dinosaurs are
the largest terrestrial vertebrate to have lived on Earth. This size must have posed
special challenges for the musculoskeletal system. Scaling theory shows that
body mass and hence the loads that must be overcome increases with body size
more rapidly than either the ability of the muscles to generate force, or the
ability of the skeleton to support these loads. Here we demonstrate how one of
the very largest sauropods, Argentinosaurus huinculensis (40 metres long, weighing
83 tonnes), may have moved. A musculoskeletal model was generated using data
captured by laser scanning a mounted skeleton and assigning muscle properties
based on comparative data from living animals. Locomotion is generated using
forward dynamic simulation to calculate the accelerations produced by the muscle
forces, coupled with machine learning techniques to find a control pattern that
minimises metabolic cost. The simulation demonstrates that at such vast body
size, joint range of motion needs to be restricted to allow sufficient force
generation for an achievable muscle mass. However when this is done, a
perfectly plausible gait can be generated relatively easily. Whilst this model
represents the best current simulation of the gait of these giant animals, it
is likely that there are as yet unknown mechanical mechanisms, possibly based
on passive elastic structures that should be incorporated to increase the efficiency
of the animal`s locomotion. It is certainly the case that these would need to
be incorporated into the model to properly assess the full locomotor
capabilities of the animal.
Sellers, W.I., Margetts,
L., Coria, R.A. and Manning, P.L. 2013. March of the Titans:
The Locomotor Capabilities of Sauropod Dinosaurs. PLoS ONE 8(10): e78733. doi:10.1371/journal.pone.0078733
Katepensaurus goicoecheai a Late Cretaceous Rebbachisaurid from central Patagonia
0 comentarios Publicado por Leonardo Filippi en 7:31
Lucio M. Ibiricu, Gabriel A. Casal,
Rubén D. Martínez, Matthew C. Lamanna, Marcelo Luna, And Leonardo Salgado.
We
describe Katepensaurus goicoecheai, gen. et sp. nov., a diplodocoid
sauropod dinosaur from the Bajo Barreal Formation (Upper Cretaceous: Cenomanian–Turonian)
of south-central Chubut Province, central Patagonia, Argentina. The holotypic
specimen is a closely associated partial axial skeleton that includes cervical,
dorsal, and caudal vertebrae. The dorsal vertebrae of Katepensaurus exhibit
the following distinctive characters that we interpret as autapomorphies: (1)
internal lamina divides lateral pneumatic fossa of centrum; (2) vertical ridges
or crests present on lateral surface of vertebra, overlying neurocentral
junction; (3) pair of laminae in parapophyseal centrodiapophyseal fossa; (4)
transverse processes perforated by elliptical fenestrae; and (5) well-defined,
rounded fossae on lateral aspect of postzygapophyses. Based on the results of previous
phylogenetic analyses, we regard the new taxon as a member of Rebbachisauridae;
more specifically, it may pertain to Limaysaurinae, a rebbachisaurid subclade
that, to date, is definitively known only from southern South America. As
currently understood, the rebbachisaurid fossil record suggests that the clade
achieved its greatest taxonomic diversity within a few million years of its
extinction during the early Late Cretaceous.
Ibiricu,
L.M., Casal, G.A., Martínez, R.D., Lamanna, M.C., Luna, M. And Salgado, L.
2013. Katepensaurus goicoecheai, gen.
et sp. nov., a Late Cretaceous Rebbachisaurid (Sauropoda, Diplodocoidea) from
central Patagonia, Argentina. Journal of Vertebrate Paleontology
33(6):1351–1366.
Finaliza exitosamente la campaña paleontológica del MAU en Cerro Overo / La Invernada. Luego de trabajar durante quince días, el equipo del Museo Argentino Urquiza integrado por el paleontólogo Leonardo Filippi y los Técnicos Carlos Fuentes y Salvador Palomo, junto al geólogo y Director del MOZ (Museo Olsacher de Zapala) Alberto Garrido y además con la participación del paleontólogo Rubén Juarez Valieri, pudieron realizar dos excavaciones simultaneas que permitieron recuperar los restos parciales de al menos dos dinosaurios saurópodos titanosaurios, un dinosaurio terópodo y un ejemplar de tortuga. Todos estos ejemplares provienen de niveles del Cretácico Superior, tentativamente de la Formación Bajo de la Carpa. Debido a la cantidad y buena preservación de los materiales, se pretende continuar con las excavaciones el año próximo, las que han sido financiadas gracias al apoyo de la empresa Exxon Mobil.
The Behavioral Implications of a Multi-Individual Bonebed of a Small Theropod Dinosaur.
0 comentarios Publicado por Leonardo Filippi en 7:40
Lucio M. Ibiricu, Rubén
D. Martínez, Gabriel A. Casal, Ignacio A. Cerda
Central Patagonia,
Argentina, preserves an abundant and rich fossil record. Among vertebrate
fossils from the Upper Cretaceous Bajo Barreal Formation of Patagonia, five
individuals of the small, non-avian theropod dinosaur Aniksosaurus darwini were recovered. Group behavior is an important
aspect of dinosaur paleoecology, but it is not welldocumented and is poorly
understood among non-avian Theropoda. The taphonomic association of individuals
from the Bajo Barreal Formation and aspects of their bone histology suggest
gregarious behavior for Aniksosaurus,
during at least a portion of the life history of this species. Histology
indicates that the specimens were juvenile to sub-adult individuals. In addition,
morphological differences between individuals, particularly proportions of the
appendicular bones, are probably related to body-size dimorphism rather than
ontogenetic stage. Gregarious behaviour may have conferred a selective
advantage on Aniksosaurus
individuals, contributing to their successful exploitation of the Cretaceous
paleoenvironment preserved in the Bajo Barreal Formation. The monospecific
assemblage of Aniksosaurus specimens
constitutes only the second body fossil association of small, coelurosaurian
theropods in South America and adds valuable information about the
paleoecologies of non-avian theropod dinosaurs, particularly in the early Late
Cretaceous of Patagonia.
Ibiricu, L. M., Martínez,
R. D., Casal, G. A., and Cerda, I. A. 2013. The Behavioral Implications of a Multi-Individual
Bonebed of a Small Theropod Dinosaur. PloS ONE 8(5): e64253.
doi:10.1371/journal.pone.0064253Se da comienzo al estudio de varios ejemplares de tortugas fósiles en el MAU
0 comentarios Publicado por Leonardo Filippi en 7:20
Una importante investigación se lleva adelante en el MAU (Museo Municipal Argentino Urquiza de Rincón de los Sauces, Neuquén); el paleontólogo del Museo de Historia Natural de San Rafael, Mendoza, Marcelo De La Fuente, comenzó con el estudio de varis ejemplares de tortugas fósiles del Cretácico Superior, halladas en zonas próximas a la localidad.
Se están estudiando tortugas del período cretácico que fueron halladas durante varios trabajos de campo realizados por el paleontólogo de Rincón, Leonardo Filippi. Es un material muy interesante, ya que son restos bastante completo y bien preservados de tortugas qu pertenecen a un grupo que tiene representantes actuales. Lo interesante de esto es que se trata de una especie que ha pasado los límites de extinción cretácica-paleocénica, límite que no cruzaron, entre otros grupos, los dinosaurios, por ejemplo.
La idea es profundizar en un estudio que permita elaborar un trabajo científico que documente estos ejemplares, los que se suman a otros vertebrados entre dinosaurios, cocodrilos y serpientes, recuperados en el marco de un proyecto que tiene como objeto conocer la fauna de fósiles del norte neuquino en inmediaciones de Rincón de los Sauces.
Se están estudiando tortugas del período cretácico que fueron halladas durante varios trabajos de campo realizados por el paleontólogo de Rincón, Leonardo Filippi. Es un material muy interesante, ya que son restos bastante completo y bien preservados de tortugas qu pertenecen a un grupo que tiene representantes actuales. Lo interesante de esto es que se trata de una especie que ha pasado los límites de extinción cretácica-paleocénica, límite que no cruzaron, entre otros grupos, los dinosaurios, por ejemplo.
La idea es profundizar en un estudio que permita elaborar un trabajo científico que documente estos ejemplares, los que se suman a otros vertebrados entre dinosaurios, cocodrilos y serpientes, recuperados en el marco de un proyecto que tiene como objeto conocer la fauna de fósiles del norte neuquino en inmediaciones de Rincón de los Sauces.
Nueva especie se tortuga terrestre gigante del Género Chelonoidis
0 comentarios Publicado por Leonardo Filippi en 15:36
Gerardo Gabriel Zacarías, Marcelo
Saúl De La Fuente, Marta Susana Fernández y Alfredo Eduardo Zurita
Se presenta una nueva especie de
tortuga terrestre gigante recuperada de la sección superior del miembro
inferior de la Formación Toropí/ Yupoí (Pleistoceno tardío, 58–22 ka). El
holotipo fue hallado en Arroyo Toropí, 10 km al sur de la localidad de Bella
Vista, Provincia de Corrientes, Argentina. Presenta escudos pectorales del plastrón
más estrechos en la línea media y expandidos hacia las marginales en sentido
antero-posterior, que permite asignarlo al género Chelonoidis fitzinger. Posee
caparazón con márgenes laterales no paralelos, placas periféricas del puente
lobuladas, una depresión proximal muy marcada con forma subelíptica sobre las
placas periféricas III en ambos lados del caparazón dorsal, y un entoplastrón
subromboidal proximalmente amplio, con proyección distal que cruza
completamente el escudo pectoral, que permiten reconocerlo como una nueva
especie, Chelonoidis lutzae sp. nov. El consenso estricto del análisis
filogenético del clado Chelonoidis exhibe una politomía entre Ch. lutzae sp.
nov., ?Ch. gallardoi (Rovereto), ?Ch. australis (Moreno) y los grupos
carbonaria y chilensis. El grupo carbonaria incluye a Ch. denticulata
(Linnaeus) y al clado formado por Ch. carbonaria (Spix) y Ch. hesterna
(Auffenberg). El grupo chilensis, incluye dos subclados, uno integrado por Ch.
chilensis (Gray), Ch. petersi (Freiberg) y Ch. nigra (Quoy y Gaimard), y otro formado
por YPFB-PAL 0932 y Ch. gringorum (Simpson). Utilizando la opción “pruned tree”
del TNT, se recupera un subclado formado por “tortugas terrestres gigantes
continentales extintas” (Ch. lutzae sp. nov. y ?Ch. australis), claramente
diferenciado de las tortugas gigantes de Galápagos.
Zacarías, G.G., De
La Fuente, M. S., Fernández, M. S. y Zurita, A. E.2013 Nueva especie se tortuga
terrestre gigante del Género Chelonoidis
fitzinger, 1835 (Cryptodira: Testudinidae), del Miembro Inferior de la Formación
Toropí/ Yupoí (Pleistoceno Tardío/ Lujanense), Bella Vista, Corrientes,
Argentina. Ameghiniana 50 (3): 298 – 318.
Overosaurus paradasorum, a new sauropod dinosaur from Rincón de los Sauces
1 comentarios Publicado por Leonardo Filippi en 14:21
Rodolfo
A. Coria, Leonardo S. Filippi, Luis M. Chiappe, Rodolfo García y Andrea B.
Arcucci
A new lithostrotian
sauropod, the small-sized Overosaurus paradasorum n. gen et sp. from the Anacleto Formation (Cam-panian, Late Cretaceous, Neuquén Group,
Patagonia, Argentina) is here described. The specimen (MAU-Pv-CO-439) consists of a fully articulated
vertebral series from the 10th cervical to the 20th caudal vertebra, the last
cervical ribs, several dorsal ribs in articulation with their respective
vertebrae, the complete right ilium and fragments of the left ilium. Overosaurus
paradasorum is diagnosed by a unique combination of
characters that includes (1) posterior cervical vertebrae with long pre- and
postzygapophyses that project beyond the anterior and posterior borders of the
centrum, respectively, (2) postspinal lamina absent in all dorsal neural
spines, (3) wide and massive 9th and 10th caudal centra that are slightly
exca-vated laterally and have relatively flat ventral surfaces, (4) laminar
projection on the posterior border of the second and third dorsal rib, (5)
ilium proportionally shorter anteroposteriorly and taller dorsoventrally than
in other lithostrotians, and (6) the preacetabular process of the ilium
strongly deflected laterally and with a ventrolaterally tapering end. Analysis
of the phylogenetic relationships of Overosaurus places it within the Aeolosaurini,
as the sister taxon of a monophyletic group formed by Aeolosaurus rionegrinus, A. maximus, Gondwanatitan faustoi and
Pitekunsaurus
macayai. Overosaurus is a
new representative of a highly diversified assemblage of Campanian
lithostrotians from Patagonia that includes both Aeolosaurini
and saltasaurids (e.g. Saltasaurus, Neuquensaurus) this small new taxon
falls within the low end of the size spectrum represented by these Late
Cretaceous sauropods.
Coria, R. A., Filippi, L. S., Chiappe, L. M., García, R.
& Arcucci, A. B. 2013. Overosaurus
paradasorum gen. et sp. nov., a new sauropod dinosaur (Titanosauria:
Lithostrotia) from the Late Cretaceous of Neuquén, Patagonia, Argentina. Zootaxa 3683 (4): 357-376.
Ariana Paulina Carabajal,
Juliana Sterli, Johannes Müller y André Hilger
Turtles are one
of the least explored clades regarding endocranial anatomy with few available
descriptions of the brain and inner ear of extant representatives. In addition,
the paleoneurology of extinct turtles is poorly known and based on only a few
natural cranial endocasts. The main goal of this study is to provide for the
first time a detailed description of the neuroanatomy of an extinct turtle, the
Late Jurassic Plesiochelys etalloni, including internal carotid circulation,
cranial endocast and inner ear, based on the first digital 3D reconstruction
using micro CT scans. The general shape of the cranial endocast of P. etalloni
is tubular, with poorly marked cephalic and pontine flexures. Anteriorly,
the olfactory bulbs are clearly differentiated suggesting larger bulbs than in
any other described extinct or extant turtle, and indicating a higher capacity
of olfaction in this taxon. The morphology of the inner ear of P. etalloni
is comparable to that of extant turtles and resembles those of slow-moving terrestrial
vertebrates, with markedly low, short and robust semicircular canals, and a
reduced lagena. In P. etalloni the arterial pattern is similar to that
found in extant cryptodires, where all the internal carotid branches are
protected by bone. As the knowledge of paleoneurology in turtles is scarce and
the application of modern techniques such as 3D reconstructions based on CT
scans is almost unexplored in this clade, we hope this paper will trigger
similar investigations of this type in other turtle taxa.
Carabajal AP, Sterli J, Müller J,
Hilger A (2013) Neuroanatomy of the Marine Jurassic Turtle Plesiochelys
etalloni (Testudinata, Plesiochelyidae). PLoS ONE 8(7): e69264.
doi:10.1371/journal.pone.0069264
New species of Meiolaniform turtle from Patagonia
0 comentarios Publicado por Leonardo Filippi en 14:46
Juliana Sterli, Marcelo S. De la Fuente e Ignacio A.
Cerda
Una nueva
especie de meiolaniforme, Trapalcochelys sulcata gen. nov. sp. nov., de
la Formación Allen (Campaniano tardío–Maastrichtiano temprano), Patagonia,
Argentina, es presentada en este trabajo. Los restos postcraneanos pertenecientes
a esta nueva especie son descriptos macroscópicamente (e.g., morfología
externa) y microscópicamente (e.g., cortes histológicos del caparazón). Trapalcochelys
sulcata gen. nov. sp. nov. comparte con otros meiolaniformes la presencia
de surcos entre los escudos marginales marcadamente curvados anteriormente y la
ornamentación de las placas dérmicas del caparazón constituida por pequeños
forámenes. Esta nueva especie difiere de la otra especie de meiolaniforme del
Cretácico Superior de Patagonia —Patagoniaemys gasparinae— en el tamaño
general y en la forma de la neural 1. La histología ósea está caracterizada por
una estructura diploe, donde una capa externa e interna de tejido compacto
circundan una región de hueso esponjoso. El hueso compacto está compuesto
mayormente por paquetes entrelazados de fibras estructurales. La abundancia de
fibras estructurales en la corteza interna y la presencia de grandes canales
vasculares tubulares son los caracteres histológicos mas distintivos de T.
sulcata. Además, una revisión exhaustiva de los restos de Meiolaniformes
del Cretácico Superior de Sudamérica es presentada. El registro sudamericano
conocido de Meiolaniformes del Cretácico Superior está restringido a Argentina
y en esta revisión hasta seis localidades han sido reconocidas. Se corrobora
que los Meiolaniformes son un componente de la asociación sudamericana Alleniana
de tetrápodos de edad campaniana tardía–maastrichtiana temprana.
Sterli, J., De
la Fuente, M. S. y Cerda, I. A. 2013. New species of Meiolaniform turtle and a
revision of the Late Cretaceous Meiolaniformes of South America. Ameghiniana 50
(2): 240-256.
The dentition of Manidens condorensis (Ornithischia; Heterodontosauridae) from the Jurassic Cañadón Asfalto Formation of Patagonia
0 comentarios Publicado por Leonardo Filippi en 14:26
Marcos G. Becerraa, Diego Pol, Claudia
A. Marsicano and Oliver W.M. Rauhut
The
recently described Manidens condorensis is one of the most completely known
taxa of the family Heterodontosauridae from the southern landmasses. However,
some dental aspects are not well known due to preservational problems in the
type material. This contribution reports new isolated teeth found in the
Canñadón Asfalto Formation (Early-Middle Jurassic). These teeth are referred
to Manidens condorensis based on the presence of autapomorphic characters of
the unusual dentition of this taxon, such as the highly asymmetric tooth crowns
and small crenulations on each denticles. The isolated crowns are well
preserved and reveal the presence of undescribed and new autapomorphical
features, including apical and basal wear facets on the occlusal surface of
isolated crowns and a wear surface also in the caniniform tooth. We carried out
statistical analyses (including morphogeometrical and discriminant analyses),
using the holotype crowns as a morphological starting point, for characterising
shape variation of the crowns along the toothrow and for identifying the
position of isolated crowns. These analyses allow defining morphological
regions within the postcaniniform toothrow and produce a metrically based
discriminant function to predict the hypothetical position of future
discoveries, providing a methodological framework that could be applied to
other extinct heterodont dinosaurs.
Marcos G. Becerra , Diego Pol ,
Claudia A. Marsicano & Oliver W.M. Rauhut (2013). The dentition of Manidens condorensis (Ornithischia;
Heterodontosauridae) from the Jurassic Cañadón Asfalto Formation of Patagonia: morphology,
heterodonty and the use of statistical methods for identifying isolated teeth,
Historical Biology: An International Journal of Paleobiology,
DOI:10.1080/08912963.2013.794227
The titanosaur sauropods from the Allen Formation of Salitral Moreno, Río Negro, Argentina
0 comentarios Publicado por Leonardo Filippi en 14:19
Rodolfo García y Leonardo Salgado
The
dinosaur record of the Salitral Moreno locality (Río Negro Province, Argentina)
is characterized by a high diversity of herbivore taxa, among them hadrosaurs, ankylosaurs,
and titanosaur sauropods, but carnivores are rare, consisting of only a few
fragmentary bones of small forms. Titanosaurs are represented by Rocasaurus
muniozi and Aeolosaurus sp., and at least four other taxa,
represented by fragmentary material. The elements preserved include a cervical,
dorsal and caudal vertebrae, chevron, humerii, ulnae, radii, metacarpal,
femora, tibiae, metatarsal, ischia, pubis, and ilium. The Allen Formation is
thought to be correlated with the Marília Formation in Brazil, and their faunas
have certain elements in common such as aeolosaurines, but saltasaurines and
hadrosaurs, are known exclusively from the Allen Formation. These absences, and
particularly that of the saltasaurines, may be because those sauropods
originated late in the Cretaceous, probably in southern South America (Northern
Patagonia?), and they did not have time to disperse to northern South America.
Garcia, R.A. and
Salgado, L. 2013. The titanosaur sauropods from the late Campanian–early Maastrichtian
Allen Formation of Salitral Moreno, Río Negro, Argentina. Acta
Palaeontologica Polonica 58 (2): 269–284.
Palaeopathological Survey of a Population of Mapusaurus
0 comentarios Publicado por Leonardo Filippi en 8:31
Phil R. Bell and Rodolfo A. Coria
Paleoepidemiology
(the study of disease and trauma in prehistoric populations) provides insight
into the distribution of disease and can have implications for interpreting
behavior in extinct organisms. A monospecific bonebed of the giant carcharodontosaurid
Mapusaurus (minimum number of individuals = 9) from the Cañaadón del Gato
site, Neuquén Province, Argentina (Cenomanian) provides a rare opportunity to
investigate disease within a single population of this important apex predator.
Visual inspection of 176 skeletal elements belonging to a minimum of nine
individuals yielded a small number of abnormalities on a cervical vertebra, two
ribs, pedal phalanx, and an ilium. These are attributed to traumatic (two cases),
infectious (two cases) and anomalous (one case) conditions in a minimum of one
individual. The emerging picture for large theropod (abelisaurids, allosaurids,
carcharodontosaurids, tyrannosaurids) populations suggests that 1) osseous abnormalities
were relatively rare (7–19% of individuals) but consistently present, and 2)
trauma was a leading factor in the frequency of pathological occurrences,
evidence of an active, often perilous lifestyle.
Filippi, L. S., Martinelli, A. G. y Garrido, A. C.
The clade
Aeolosaurini is represented by several specimens found, so far, only in
Argentina and Brazil. The material reported here corresponds to a sauropod
titanosaur consisting of four incomplete anterior caudal vertebrae, from the
Narambuena Paleontological Site, Rincón de los Sauces, Neuquén Province,
Argentina. The specimen comes from the Plottier Formation (late Coniacian-lower
Santonian, Upper Cretaceous), Neuquén Group. The specimen has a combination of
features that includes it into the clade Aeolosaurini: anterior caudal centra
with anterodorsal margin bent forward; prezygapophyses elongated in anterior
caudal, in correlation with the extreme displacement of the neural arch
forward; and anteroposteriorly elongated articular facets of prezygapophyses,
at least in the anterior caudals. However, it differs from other Aeolosaurini
by having postzygapophysis with anteroposteriorly short articular facets, not
as elongated in the prezygapophyses. This specimen corresponds not only to the
fi rst discovery of an Aeolosaurini in the north of the Neuquén Basin (because Rinconsaurus
caudamirus Calvo & Gonzalez Riga has been included in another clade,
Rinconsauria), but also the oldest record of the group.
Filippi, L. S., Martinelli, A. G. y Garrido, A.
C. 2013. Registro de un dinosaurio
Aeolosaurini (Sauropoda, Titanosauria) en el Cretácico Superior (Formación
Plottier) del Norte de la Provincia de Neuquén, Argentina, y comentarios sobre los Aeolosaurini
sudamericanos. Revista Brasilera de Paleontología 16 (1): 147-156.
First Occurrence of stomach stones in Pterosaurs
0 comentarios Publicado por Leonardo Filippi en 15:09
Laura Codorniú, Luis M. Chiappe, and Fabricio D. Cid.
Two nearly complete
skeletons of the filter-feeding pterodactyloid Pterodaustro guinazui from the Lowe Cretaceous of Argentina exhibit
clusters of poorly sorted coarse sand to fine gravel inside the abdominal
cavity. These stones are interpreted as ingested gastroliths (geogastroliths),
which are commonly found in a variety of archosaurs (including birds) but have
never before been reported in a pterosaur. The geogastroliths found in these Pterodaustro specimens are interprete as
having assisted in the digestion of hard food items such as ‘shelled’
crustaceans that are abundant in the fossil beds of this pterosaur. One of
these specimens with geogastroliths has anteriormandibular teeth that are
notably thicker than the posterior teeth and are somewhat procumbent. We
suggest that these teeth might have facilitated the apprehension of fine
gravel.
Codorniú, L., Chiappe,
L.M. and Cid, F.D. 2013. First Occurrence of stomach stones in Pterosaurs.
Journal
of Vertebrate Paleontology 33(3): 647–654.
Huevos de saurópodos de la Fm. Cerro Barcino Chubut, Argentina
0 comentarios Publicado por Leonardo Filippi en 15:19
Eloísa Argañaraz,
Gerald Grellet-Tinner, Lucas E. Fiorelli, J. Marcelo Krause y Oliver W. M.
Rauhut
Para efectuar
una interpretación paleobiológica del primer material oológico hallado en la
provincia de Chubut, inferir su escenario paleoambiental y compararlo con
huevos de dinosaurios de otras áreas, se describen detalladamente varios
fragmentos y dos huevos fósiles incompletos provenientes de la localidad de
Huanimán, en el centro-norte de la provincia. El material fue extraído en una
arenisca tobácea fina, depositada en facies de planicie de inundación proximal
asociada a canales multiepisódicos sinuosos. Esta roca es asignable al Miembro
Cerro Castaño de la Formación Cerro Barcino (Aptiano–Albiano). La morfología de
las cáscaras es similar a la de otros huevos megalolítidos (un grupo
parafilético en la parataxonomía de huevos) de Patagonia tales como los de Auca
Mahuevo (Neuquén), identificados como huevos de saurópodos titanosaurios a
partir de embriones in ovo, y los de Salitral Moreno (Río Negro). Sin
embargo, este nuevo material de Chubut, presenta un nuevo carácter estructural.
La red de poros horizontal se ubica debajo de la superficie nodular, a
diferencia de los huevos neuquinos donde se encuentra sobre la membrana
testácea. Este carácter morfológico y el grosor de cáscara (1.5 mm), sugieren una
novedosa adaptación a un ambiente específico de nidificación. Aunque sólo se
han encontrado dos huevos aislados en Huanimán, este descubrimiento puede
implicar la existencia de un nuevo sitio de nidificación en el área.
Argañaraz, E., Grellet-Tinner, G.,
Fiorelli, L.E., Krause, J. M. y Rauhut, O.W.M. 2013. Huevos
de Saurópodos del Aptiano–Albiano, Formación Cerro Barcino (Patagonia,
Argentina): Un enigma Paleoambiental y Paleobiológico. Ameghiniana 50 (1):
33-50.
Trabajos de campo confirman el enorme tamaño del nuevo ejemplar
0 comentarios Publicado por Leonardo Filippi en 8:51
Durante la primera mitad del mes de abril, el MAU (Museo Municipal Argentino Urquiza), Rincón de los Sauces, Neuquén, reanudó los trabajos de campo en Cañadón Mistringa. En este sitio fue hallado durante el 2012 un enorme ejemplar de dinosaurio saurópodo titanosaurio. Durante estos trabajos se recuperaron algunos huesos que dan cuenta del gran tamaño del animal: una escápula incompleta que se estima superaría el 1,50 m de longitud y una enorme vértebra cervical (bochón de la foto) cuyas medidas estimadas superarían el 1,20 m de ancho, 0,90 m de largo y 1 m de alto aproximadamente. Las tareas de recuperación de este gigante recién comienzan, por lo que todavía será necesario remover varios metros cúbicos de roca, para así, extraer nuevas piezas que permitan estimar el tamaño real del ejemplar, el cual se cree, estaría entre los 30 y 35 m de longitud.
Análisis de cáscaras de huevos de dinosaurio de la Formación Allen, Río Negro, Argentina.
0 comentarios Publicado por Leonardo Filippi en 8:31
Mariela S. Fenández
El presente
estudio es una contribución más al conocimiento de la parataxonomía de las
cáscaras de huevos de dinosaurios procedentes del Salitral de Santa Rosa y
Salitral Ojo de Agua de la provincia de Río Negro, Argentina. Para dicho
trabajo fueron estudiados 4469 fragmentos de cáscaras de huevos de la Formación
Allen, Cretácico Superior (Campaniano-Maastrichtiano). Doce de estas cáscaras
fueron sometidas a un Análisis de Componentes Principales, para clasificarlas y
analizar las relaciones entre los caracteres utilizados comúnmente en las
clasificaciones parataxonómicas. Por otra parte se estudiaron 4264 cáscaras con
lupa binocular, 57 cáscaras con microscopio óptico y microscopio de
polarización y por último 14 cáscaras con microscopio electrónico de barrido.
Fueron identificados dos grandes grupos, cáscaras del tipo 1 afines a la
oofamilia Megaloolithidae con cinco subtipos y cáscaras del tipo 2, sin
subtipos. Los caracteres relevantes encontrados con el estudio de ACP fueron:
el espesor de la cáscara, la anchura de las unidades de cáscara, el diámetro de
los nódulos y el diámetro de las mamilas. Los diferentes tipos de cáscaras
registrados fueron comparados con diversos ootaxones de América del Sur y del
resto del mundo.
Fernández, M.S. 2013.
Análisis de
cáscaras de huevos de Dinosaurios de la Formación Allen, Cretácico Superior de
Río Negro (Campaniano-Maastrichtiano): Utilidad de los macrocaracteres de
interés parataxonómico. Ameghiniana 50 (1): 79-97.
Avian eggs from the Late Cretaceous of Patagonia
0 comentarios Publicado por Leonardo Filippi en 8:22
Mariela S. Fernández, Rodolfo
A. García, Lucas Fiorelli, Alejandro Scolaro, Rodrigo B. Salvador, Carlos
N. Cotaro, Gary W. Kaiser y Gareth J. Dyke
We report the
first evidence for a nesting colony of Mesozoic birds on Gondwana: a fossil
accumulation in Late Cretaceous rocks mapped and collected from within the
campus of the National University of Comahue, Neuquén City, Patagonia (Argentina).
Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes,
nested in an arid, shallow basinal environment among sand dunes close to an
ephemeral water-course. We mapped and collected 65 complete, nearcomplete, and
broken eggs across an area of more than 55 m2. These eggs were laid either
singly, or occasionally in pairs, onto a sandy substrate. All eggs were found
apparently in, or close to, their original nest site; they all occur within the
same bedding plane and may represent the product of a single nesting season or
a short series of nesting attempts. Although there is no evidence for nesting
structures, all but one of the Comahue eggs were half-buried upright in the
sand with their pointed end downwards, a position that would have exposed the
pole containing the air cell and precluded egg turning. This egg position is
not seen in living birds, with the exception of the basal galliform megapodes
who place their eggs within mounds of vegetation or burrows. This accumulation
reveals a novel nesting behaviour in Mesozoic Aves that was perhaps shared with
the non-avian and phylogenetically more basal troodontid theropods.
Fernández MS, García RA, Fiorelli
L, Scolaro A, Salvador RB, et al. (2013) A Large Accumulation of Avian Eggs
from the Late Cretaceous of Patagonia (Argentina) Reveals a Novel Nesting
Strategy in Mesozoic Birds. PLoS ONE 8(4): e61030.
doi:10.1371/journal.pone.0061030
Morfología e histología de los osteodermo de un nuevo crocodyliforme de Rincón de los Sauces, Neuquén.
0 comentarios Publicado por Leonardo Filippi en 14:50
Filippi L. S., Cerda I. A. y Garrido, A. C.
Resumen. Se describen
osteodermos de un nuevo ejemplar de crocodyliforme hallado en un afloramiento
correspondiente a niveles de la Formación Plottier (Coniaciano tardío) de la
localidad de Puesto Hernández, en inmediaciones de la localidad de Rincón de los
Sauces, Provincia del Neuquén. Los osteodermos estudiados, que son parte del
material hallado, están integrados por: región dorso-sacra, osteodermos
apendiculares asociados al fémur derecho, región proximoventral de osteodermos
caudales articulados y osteodermos aislados. La histología de los osteodermos
permitió determinar que están constituidos por una corteza compacta que
circunda una región interna más porosa. Fue posible reconocer marcas de
crecimiento (annuli) en prácticamente todo el tejido compacto, pudiendo
determinarse una edad mínima de 18 años para el espécimen estudiado. Los
osteodermos exhiben caracteres que permiten preliminarmente asignar al ejemplar, como un Mesoeucrocodylia cercanamente relacionado con
Peirosauridae.
Abstract. Osteoderms of a new crocodyliform
specimen recovered from the Puesto Hernández locality are described here, found
in sediments of the Plottier Formation (late Coniacian), near Rincón de los
Sauces city, Neuquén Province. The studied osteoderms, that are part of the
associated material, include: dorso-sacral region, appendicular osteoderms
associated to the right femur, proximoventral region of articulated caudal
osteoderms, and isolated osteoderms. The histology of the osteoderms allowed
determining they have a compact cortex that surrounds a more cancellous
internal region. It was possible to recognize growth marks (annuli) in the
entire compact tissue, indicating a minimum age of 18 years for the studied
specimen. The osteoderms have characters that allow preliminarily assigning the
specimen to Mesoeucrocodylia closely related to Peirosauridae.
Filippi, L.S., Cerda, I.A. y Garrido, A. C.
2013 Morfología e histología de los osteodermos de un peirosauridae de la
Cuenca Neuquina. Ameghiniana 50 (1):3-13.
Early basicranial evolution and the origins of Crocodyliformes
0 comentarios Publicado por Leonardo Filippi en 15:06
Diego Pol, Oliver W. M.
Rauhut, Agustina Lecuona, Juan M. Leardi, Xing Xu and James M. Clark
Extant crocodylians
have a limited taxonomic and ecological diversity but they belong to a lineage
(Crocodylomorpha) that includes basal and rather generalized species and a
highly diverse clade, Crocodyliformes. The latter was among the most successful
groups of Mesozoic tetrapods, both in terms of taxonomic and ecological
diversity. Crocodyliforms thrived in terrestrial, semiaquatic, and marine
environments, and their fossil diversity includes carnivorous, piscivorous,
insectivorous, and herbivorous species. This remarkable ecological and trophic
diversity is thought only to occur in forms with a completely akinetic skull,
characterized by a functionally integrated and tightly sutured
braincase-quadrate-palate complex. However, the patterns of evolutionary change
that led to the highly modified skull of crocodyliforms and that likely enabled
their diversification remain poorly understood. Herein, a new basal
crocodylomorph from the Late Jurassic of Patagonia is described, Almadasuchus
figarii gen. et sp. nov. The new taxon is known from a well-preserved posterior
region of the skull as well as other craniomandibular and postcranial remains.
Almadasuchus figarii differs from all other crocodylomorphs in the presence of
six autapomorphic features, including the presence of a large lateral notch on
the upper temporal bar, an otic shelf of the squamosal that is wider than long,
a deep subtriangular concavity on the posterolateral surface of the squamosal,
and an elongated pneumatopore on the ventral surface of the quadrate.
Phylogenetic analysis focused on the origin of Crocodyliformes places
Almadasuchus as the sister group of Crocodyliformes, supported by synapomorphic
features of the skull (e.g. subtriangular basisphenoid, absence of
basipterygoid process, absence of a sagittal ridge on the frontal, and a flat
anterior skull roof with an ornamented dorsal surface). New braincase
information provided by Almadasuchus and other crocodylomorphs indicates that
most of the modifications on the posterior region of the skull of
crocodyliforms, including the strongly sutured braincase, quadrate, and the
extensive secondary palate appeared in a stepwise manner, and pre-dated the
evolutionary changes in the snout, jaws, and dentition. This indicates that the
progressively increased rigidity of the skull provided the structural framework
that allowed the great ecological diversification of crocodyliforms during the
course of the Mesozoic. The phylogenetic pattern of character acquisition
inferred for the strongly sutured (akinetic) skull and the appearance of more
diverse feeding behaviours that create high mechanical loads on the skull
provides another interesting parallel between the evolution of Mesozoic
crocodyliforms and the evolutionary origins of mammals.
Pol, D., Rauhut, O.W.M., Lecuona, A., Leardi, J. M., Xu. X. and Clark, J.M. 2013
A new fossil from the Jurassic of
Patagonia reveals the early basicranial evolution and the origins of
Crocodyliformes. Biological Reviews.
doi: 10.1111/brv.12030
Philip J. Currie y Ariana Paulina Carabajal
There were considerable
differences in Late Cretaceous faunas of the Northern and Southern Hemispheres,
although the differences were breaking down during Campanian and Maastrichtian
times with the appearance of hadrosaurids in Antarctica and South America, and titanosaurids
in North America. However, theropods continued to be separated into northern
and southern faunas until paravians were discovered in the Southern Hemisphere
(Novas and Puerta, 1997; Forster et al. 1998; Calvo et al. 2004; Makovicky et
al. 2005; Novas and Pol, 2005; Novas et al. 2008). During the 2008 field
season, a joint expedition to the Bajo de Santa Rosa (Río Negro, Argentina)
recovered a second, slightly smaller specimen of Austroraptor cabazai Novas,
Pol, Canale, Porfiri and Calvo, 2008 (Novas et al. 2008; Paulina Carabajal et
al., 2009). The specimen was identified on the basis of the morphology of the
humerus, metatarsal III and pedal phalanx IV-2 (originally identified as IV-1
in the holotype, MML 195). Although the skeleton is incomplete, it preserves
bones (radius, ulna, and elements of the metacarpus, metatarsus and pes) that
were not recovered with the holotype of this large dromaeosaurid. The
description of this second specimen is intended to complement the description
of the holotype (Novas et al., 2008), adding information about the limb
morphology, particularly the forelimb and foot of this dinosaur.
Currie, P.J. y Paulina Carabajal, A. 2012.
A new specimen of
Austroraptor cabazai Novas, Pol, Canale, Porfiri and Calvo, 2008 (Dinosauria,
Theropoda, Unenlagiidae) from the Latest Cretaceous (Maastrichtian) of Río
Negro, Ameghiniana 49(4): 662-667.
Primer registro de Pterosauria en la Fm. Bajo Barreal, Patagonia central, Argentina
0 comentarios Publicado por Leonardo Filippi en 8:25
The fossil record of
pterosaurs is relatively abundant in South America. Remains of this group have
been primarily found in Early Cretaceous rocks exposed in two different areas, i.e.,
in Northeastern Brazil (Kellner and Tomida, 2000) and in San Luis Province,
Central Argentina (Bonaparte, 1970). Excepting the records in Neuquén Province,
the fossil record of pterosaurs in Patagonia (i.e., Golfo San Jorge and Austral
basins) is poor and incomplete (Codorniú and Gasparini, 2007). Continental
deposits of the Bajo Barreal Formation (Cenomanian–Turonian) exposed in Central
Patagonia, Argentina (Golfo San Jorge Basin), preserve an important record of
South American Late Cretaceous vertebrates, particularly dinosaurs (Martínez
et al., 2004; Martínez and Novas, 2006; Casal et al., 2007; Ibiricu et al.,
2010). This record has been significantly increased over the past decade. The
best known assemblages from Bajo Barreal come from the localities known as
Estancia Ocho Hermanos and Estancia Laguna Palacios. Herein we report recently
identified pterosaur material from rocks of the Bajo Barreal Formation exposed
at Estancia Ocho Hermanos and discuss the implications of this material for the
Patagonian fossil record of Pterosauria. The fossil is significant because it
adds to the generally sparse global record of Cretaceous (especially Late
Cretaceous) pterosaurs and constitutes the second most southern occurrence of Pterosauria
worldwide. This material confirms the presence of pterosaurs in the Bajo
Barreal Formation, increasing the number of taxa in the known fossil fauna from
this unit and thus our knowledge of the early Late Cretaceous vertebrate assemblages
of Central Patagonia.
Ibicuru,L. M., Martínez, R. D. y Casal, G. A. 2012. The first record of
Pterosauria in the Bajo Barreal Formation (Upper Cretaceous), central
Patagonia, Argentina. Ameghiniana 49(4): 657-661
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